Relay



R. E. DE CAMP.

RELAY.

APPLICATION mm OCT-8.1918.

1,368,326. Patented Feb. 15,1921.

Fig! 4 I5 24 I8 3 26 20 I7 4 I5 Fig. 2. WITNESSES: INVENTOR y 5 0 Camp.5174M BY 7 ATTbRNEY comprise a UNITED STATES PATIENT" OFFICE.

BAY E. DE OAIP, OP WILKINSBUBG, PENNSYLVANIA, ASSIGNOB TO WESTINGHOUIELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

may.

Application filed 0mm 8, 191a Serial No. 257,349.

and electromagnetically actuated switches for the control of electricswitches. In a more limited aspect, my invention relates to switchesthat are particularly adapted for unit-switch-control systems.

Control systems of the unit-switch type, largely used for governingelectric motors,

plurality of independently operated individual switches .or contactorsdesigned and connected to act successively to produce a gradualacceleration of the motors.

with which they are associated. In these systems, devices are ordinarilyemployed for delaying the action of the successive contactors in orderto avoid injury to the motors One form of these by excessive currents.

of auxlllary devices comprises a pluralit switches or relays forgoverning the closing of the respective contactors. My inventioncomprises a rela which, though adapted for general use, fin s particularapplication in connection with such a system. In my a plication forcurrent-limlt rela Serial 0. 241,259, filed June 21, 1918, haveillustrated several forms of such a relay. The iplresent application isconcerned with a modication.

I have illustrated my invention in connection'with a unit-switchaccelerating system, in which the closing of each contactor iscontrolled by a coil, the circuit of which is closed by a relay. Thetime of closing of the relay is determined by the degree of energizationof another 0011. Though this arrangement is by ,no means essential, Ihave illustrated the second coil as serving also the function of ablowout coil for the contactor. As in the above-mentioned application,the relay is biased toward closed position but is maintained open untilthe motor current falls to the roper value, the current itself, thusperforming the work of releasing the rela at the proper time.

An 0 ject of my invention is to provide a novel relay for particular usein a u nitswitch accelerating system.

Another object of my invention is to rovide a relay, the controllingcoil of w ich serves also as a blowout coil for one of the contactors.

Other objects of my invention will appear hereinafter.

In the drawings, Figure 1 is a partly elevatlonal and partlylongitudinal sectional .v1ew of 'my relay, and F1 2 is a diagrammaticnew of circuits an apparatus illustrating the use of this relay in amotor-accelerating system.

Referring to Fig. 1, the relay parts are supported, in any suitablemanner, upon an msulating panel 1. A pair of magnetizable pole pieces 2,lined with insulating material 3, inclose'a coil 4 between them, which,when energized by current flowing through it, creates a magnetic fieldfor attracting a plunger 5 and an armature 6. A compression spring 7serves to return the plunger 5 to normal position uponthe-deenergization of the coil 4. The force exerted by the spring 7 maybe varied by a rod 8, the position of which, with respect to the plunger5, may be adjusted, as by means of a screwthreaded connection 81. Theplunger 5 is slidably mounted in a non-magnetizable tube 9, which,together with a magnetizable core 10, is located Within the opening ofthe coil 4. The rod 8 is slidably mounted in the core 10 and within anopening in the armature 6 and is rovided with an enlargement 11 fornormal y engaging the armature 6, thereby to maintain this armature 6 inengagement with the core 10. The core 10 is adjustably secured to thetube 9 at 12, the tube 9 and the core 10 being respectively providedwith flange members 13 and 18 for clamping the parts of the arc shieldtogether. As the flange 13 is of non-magnetizable material, it servesalso to prevent freezing of the plunger 5. The parts are so designed asnormally to leave an adjustable air gap 14 between the core member 10and the plunger 5 for the purpose of regulating the reluctance of themagentic circuit. The coil 4 is insulated from the core 10 at 15.

Although I have illustrated the plunger 5 as controlling a singlearmature 6, it

Specification of Letters Patent. Patented Feb. 15, 1921.

will be obvious that, as explained in my aforementioned application, theplunger 5 may be easily so designed as to control a plurality ofarmatures 6, each controlling a relay, as hereinafter described.

The armature 6 is pivotally secured at 16 to a supporting member 17mounted upon the panel 1. A. spring 18 is coiled about a rod 19, whichis rigidly secured to the panel 1, and which passes through an openingin an arm 20 of the armature 6, this armature 6 being preferably, asillustrated, of bell-crank shape. The. tension of the spring 18 may beso adjusted, as by means of nuts 31, as to exert a force weaker thanthat of the spring 7. The arm 20 carries a movable contact member 24 forcoiip'erating with a stationary contact member 26 which is mounted uponthe panel 1. The contact members 24 and 26 constitute a relay.Obviously, the contact member 24 may be, supported by the main portionof the armature 6 and, again, as illustrated in my above-mentionedapplication, the main portion of the armature 6 and the arm 20 may bothserve to support contact members.

The coil 4, which may be a-series or a shunt coil, is adapted to beenergized upon the closing of a contactor 45 and to serve as a blowoutcoil for this contact member.

The operation is a follows: Upon the closing of the contactor 45, (Fig.2), current flows through the coil 4, whereupon a magnetic field iscreated which causes the plunger 5 to be drawn into the opening in thecoil 4 toward the core 10. The rod 8 is thereby forced outwardly, theengagement between the part 11 and the armature, 6 being thereuponreleased. If the current is above a previously selected safe value, themagnetic field will overcome the force'of the spring 18, and thearmature 6 will remain in engagement with the core 10. When the current"falls to a safe value, the spring 18 will overpower the force of themagnetic field of the core 4 and cause the closing of the contactmembers 24 and 26. In the event that the magnetic field becomes too weakto maintain the plunger 5 in actuated position, in opposition to theforce of the spring 7, this spring 7 will reactuate the plunger 5 to itsillustrated position (Fig. 1) causing the enlargement 11 to rengage thearmature 6 and to reopen the contact members 24 and 26 in opposition tothe force of the spring 18.

In Fig. 2, I have illustrated a control .system embodying the use of therelay of Fig. 1. For convenience, I employ the same reference numeralsas in ,Fig. 1, wherever, possible. An armature 38, having a compensatingfield-magnet winding 39, a series field-magnet winding 40 and a shuntfieldmagnet winding 41 is connected between the line conductors 42 and43 in series with a resistor 44. The circuit of the motor is adapted tobe closed by the line contactor 45, and the resistor 44 is ada ted to beshort-circuited by a plurality o contactors.

45, 45 and 45. The contactor 45 is actuated by a coil 52, and thecontactors 45, 45. and 45 are actuated by coils 48, 49 and 50. Aplurality of relays 6, 6 and 6 are shown as mechanically interlockedwith the plungers 5, 5 and 5*, respectively, of the blowout coils of thecontactors 45, 45 and 45" in such fashion that they will be maintainedin the open position until released upon the occurrence of currentpeaks, as described in connection with Fig. 1. The system is shown ascontrolled by a pair of push-buttons respectively designated as startand stop The contactor 45 is mechanically interlocked with a switch 51for short-circuiting the start push-button, as below described.

Upon the closing of the start? push-button, a circuit is establishedwhich extends from the line conductor 42, through the sto and startpush-buttons, and the actuating coil 52 to the line conductor 43. Thecontactor 45 is thereupon closed, causing the closing also of the switch51, which establishes a short-circuit -for the start.

push-button, so that the start push-button may thereupon be released. Acircuit is now established for the motor which extends from the lineconductor 42 through the coil 4-which controls the relay 6-the contactor45, the armature 38, the field-magnet windings 39 and 40 and theresistor 44, to the line conductor 43. A shunt circuit is alsoestablished for the field-magnet winding 41. A heavy current is thuscaused to flow through the blowout coil 4 which operates the plunger 5and releases the relay 6.

The relay 6, though releaied mechanically,

upon the occurrence of current peak 1s, nevertheless, maintained in openposition for a limited period of time until the current in the motorcircuit falls to a previously selected safe value, as explained inconnection with the description of Fig. 1. When the current falls to asufliciently low value, the rela 6 010 w'es, as described in connectionwith ig. 1, whereupon a circuit is established from the line conductor42, through the stop push-button, the relay 6 and the actuating coil 48of the contactor 45*,to the line conducor 43. The closing of 'thiscircuit, causing the energization of the safe value, dependingupon thestrength of the spring 18 (Fig. 1), connected to the relay 6", or thesize of the air gap'14 1), the relay 6 will close, whereupon a an cuitwill be established, which extends from the line conductor 42," throughthe stop push-button, the relay 6" and the actuating coil 49 of thecontactor 45", to the line conductor 43. The contactor 45 will thereuponbe closed to short-circuit another portion of the resistor 44, the coil,4",which is then en-- ergized, serving also as-a blowout coil for thecontactor 45"., In the same manner as described above, the relay 6 willclose at the proper time to cause the energization of the.

coil 50 and the consequent closing of the contactor 45 to short-c rcuitthe remaining portion ofthe resistor 44. The stop pushbutton serves todeenergize the various circuits and stopthe motor,

It will be understood that ,the circuits of Fig. 2 are illustrativeonly, and that my invention'is of essarily limite' to motor-acceleratingsystems. I desire, therefore, that my invention shall not be construedas limited except in so far as limitations maybe expressed in theappended claims.

claim as my invention:

1. The combination with a coil and a plunger slidable within the openingof said coil, of means for actuating said plunger outwardly from saidopening when said coil is denergized, an armature controlled by saidlunger, means controlled by said plunger or maintaining said armatureadjacent to said coil, and-means for biasing said armature away fromsaid coil.

neral application, not nectracted to sald core member, a rod movablewith said plunger and slidably mounted in said longitudinal opening, anarmature that is mova le relatively to said rod, means caraplungeradapted to be, at-

ried by said rod-for, controlling said arma ture and means for actuatingsald armature.

4. In a switch mechanism, the combina tion. with acoil and a switchassociated therewith, of a spring tending to close said switch, aspring-retracted lunger controlled by said coil for maintaining theswitch open when the coil 'is deenergized and an armature formaintaining the switch open a predetermined time after the coil hasbeen, energized. I

5. In a switch mechanism, the combination with a main switch having ablowout coil, of an auxiliary switch, a. spring-retracted plungerassociated with the blowout coil for maintaining the auxiliary switch inan open position, and an armature conswltch and associatedv nected tothe auxilia with the blowout 0011 for maintaining the auxiliary switchin an open position a predetermined time after the blowout coil isenergized and the auxiliary switch is released RAY E. DE CAMP.

